Environmental Chemistry

NEET Chemistry · 96 questions · Page 5 of 10 · Click an option or "Show Solution" to reveal answer

Q41

Air pollution that occurs in sunlight is :

A oxidising smog

B reducing smog

C fog

D acid rain

Correct Answer

Option A

Solution

Air pollution caused by sunlight is photochemical smog and it is oxidising.

Q42

Given below are two Statements: Statement I : Classical smog occurs in cool humid climate. It is a reducing mixture of smoke, fog and sulphur dioxide. Statement II : Photochemical smog has components, ozone, nitric oxide, acrolein, formaldehyde, PAN etc. In the light of the above statements, choose the most appropriate answer from the options given below.

A Both Statement I and Statement II are correct.

B Both Statement I and Statement II are incorrect.

C Statement I is correct but Statement II is incorrect.

D Statement I is incorrect but Statement II is correct.

Correct Answer

Option A

Solution

(I) Classical smog occurs in cool humid climate.

It is a reducing mixture of smoke, fog and sulphur dioxide.

This is a correct statement.

(II) This statement is also based on fact and is a correct statement.

Q43

The smog is essentially caused by the presence of :

A O2 and O3c

B O3 and N2

C Oxides of sulphur and nitrogen

D O2 and N2

Correct Answer

Option C

Solution

Photochemical smog is caused by oxides of sulphur and nitrogen.

Q44

The incorrect statement(s) among (a) – (d) regarding acid rain is (are) : (a) It can corrode water pipes. (b) It can damage structures made up of stone. (c) It cannot cause respiratory ailments in animals. (d) It is not harmful for trees

A (c) and (d)

B (a), (b) and (d)

C (c) only

D (a), (c) and (d)

Correct Answer

Option A

Solution

(1) Acid rain corrodes water pipes resulting in the leaching of heavy of heavy metals such as iron, lead and copper into the drinking water.

(2) Acid rain damages buildings and other structures made of stone or metal.

(3) It causes respiratory aliments in human beings and animals.

(4) It is harmful for agriculture, trees and plants as it wasshes down the nutrients needed for its growth.

Q45

The concentration of fluoride, lead, nitrate and iron in a water sample from an underground lake was found to be 1000 ppb, 40 ppb, 100 ppm and 0.2 ppm, respectively. This water is unsuitable for drinking due to high concentration of :

A Lead

B Nitrate

C Iron

D Fluoride

Correct Answer

Option B

Solution

The maximum limit of nitrate in drinking water is

50

ppm. Excess nitrate in drinking water can cause disease such as methemoglobinemia ('blue baby' syndrome).

Q46

Which one of the following statements is NOT correct?

A Eutrophication indicates that water body is polluted

B The dissolved oxygen concentration below 6 ppm inhibits fish growth

C Eutrophication leads to increase in the oxygen level in water

D Eutrophication leads to anaerobic conditions

Correct Answer

Option C

Solution

Eutrophication leads to decrease in oxygen level of water. 3rd statement is incorrect.

Q47

Given below are two statements: Statement I : In polluted water values of both dissolved oxygen and

\mathrm{BOD}

are very low. Statement II : Eutrophication results in decrease in the amount of dissolved oxygen. In the light of the above statements, choose the most appropriate answer from the options given below :

A Both Statement I and Statement II are true

B Both Statement I and Statement II are false

C Statement I is true but Statement II is false

D Statement I is false but Statement II is true

Correct Answer

Option D

Solution

Since eutrophication is result of excessive growth of weed in water bodies, which consume dissolved oxygen of water bodies.

$\therefore$ Eutrophication decreases amount of dissolved oxygen in water bodies.

Polluted water has low value of dissolved oxygen, but high valueof BOD (Biological oxygen demand), since chemical and organic matter requires dissolved oxygen to get decompose.

Q48

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Photochemical smog causes cracking of rubber. Reason (R) : Presence of ozone, nitric oxide, acrolein, formaldehyde and peroxyacetyl nitrate in photochemical smog makes it oxidizing. Choose the most appropriate answer from the options given below :

A Both (A) and (R) are true but (R) is not the true explanation of (A)

B (A) is false but (R) is true.

C (A) is true but (R) is false.

D Both (A) and (R) are true and (R) is the true explanation of (A)

Correct Answer

Option D

Solution

Photochemical smog causes cracking of rubber, the common component of photochemical smog are ozone, nitric oxide, acrolein, formaldehyde and peroxyacetyel nitrate (PAN).

Q49

Which of the following is a set of greenhouse gases?

A CH4, O3, N2, SO2

B O3, N2, CO2, NO2

C O3, NO2, SO2, Cl2

D CO2, CH4, N2O, O3

Correct Answer

Option D

Solution

The gases that contribute to greenhouse effect are called greenhouse gases. These include CO2 , CH4 , N2O and O3.

Q50

Which of the following compounds is an example of Freon?

\mathrm{C}_{2} \mathrm{H}_{2} \mathrm{F}_{2}

\mathrm{C}_{2} \mathrm{HF}_{3}

\mathrm{C}_{2} \mathrm{F}_{4}

\mathrm{C}_{2} \mathrm{Cl}_{2} \mathrm{F}_{2}

Correct Answer

Option D

Solution

Freons are a class of compounds which are also known as chlorofluorocarbons (CFCs).

As the name suggests, these compounds contain carbon, chlorine, and fluorine atoms.

So the compound that is an example of a Freon from the options given is : Option D :

\mathrm{C}_{2} \mathrm{Cl}_{2} \mathrm{F}_{2}

This compound contains both chlorine and fluorine atoms bonded to carbon, and is therefore a CFC or a Freon.

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